[PATCH] pdflush: handle resume wakeups
pdflush is carefully designed to ensure that all wakeups have some
corresponding work to do - if a woken-up pdflush thread discovers that it
hasn't been given any work to do then this is considered an error.
That all broke when swsusp came along - because a timer-delivered wakeup to a
frozen pdflush thread will just get lost. This causes the pdflush thread to
get lost as well: the writeback timer is supposed to be re-armed by pdflush in
process context, but pdflush doesn't execute the callout which does this.
Fix that up by ignoring the return value from try_to_freeze(): jsut proceed,
see if we have any work pending and only go back to sleep if that is not the
case.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/pdflush.c b/mm/pdflush.c
index df7e50b..b02102f 100644
--- a/mm/pdflush.c
+++ b/mm/pdflush.c
@@ -104,21 +104,20 @@
list_move(&my_work->list, &pdflush_list);
my_work->when_i_went_to_sleep = jiffies;
spin_unlock_irq(&pdflush_lock);
-
schedule();
- if (try_to_freeze()) {
- spin_lock_irq(&pdflush_lock);
- continue;
- }
-
+ try_to_freeze();
spin_lock_irq(&pdflush_lock);
if (!list_empty(&my_work->list)) {
- printk("pdflush: bogus wakeup!\n");
+ /*
+ * Someone woke us up, but without removing our control
+ * structure from the global list. swsusp will do this
+ * in try_to_freeze()->refrigerator(). Handle it.
+ */
my_work->fn = NULL;
continue;
}
if (my_work->fn == NULL) {
- printk("pdflush: NULL work function\n");
+ printk("pdflush: bogus wakeup\n");
continue;
}
spin_unlock_irq(&pdflush_lock);